(British)
(=series)succession fa train of eventsune succession d'événements→ a train of events which would end in tragedyto lose one's train of thoughtperdre le fil de sa pensée→ He lost his train of thought for a moment.

to set sth in trainmettre qch en route→ He praised the reforms set in train by the government.

to bring sth in its trainapporter qch avec soi→ The cars have brought in their train a host of other problems.

(for profession)
suivre une formationto train as a teachersuivre une formation d'enseignant→ She started to train as a nurse.to train to do sthsuivre une formation pour faire qch→ Stavros was training to be a priest.

(for sport)
s'entraînerto train for a races'entraîner pour une course→ He was training for the London marathon.